Svalbard

library(PlotSvalbard)
basemap("svalbard")

basemap("kongsfjorden") # or just basemap()

basemap("kongsfjordbotn")

basemap("kronebreen")

basemap("mosj")

Barents Sea

basemap("barentssea")

Barents Sea map also prints mainland Norway, but the projection is not optimal, and the resolution is quite low.

basemap("barentssea", limits = c(12, 24, 68, 71))

Pan-Arctic

basemap("arctic50")

basemap("arctic60")

Manual limits

Achieved using a numeric vector. The first element defines the minimum longitude, the second element the maximum longitude, the third element the minimum latitude and the fourth element the maximum latitude of the bounding box. The coordinates have to be given as decimal degrees for Svalbard and Barents Sea maps and as UTM coordinates for pan-Arctic maps (see ?transform_coord).

basemap("svalbard", limits = c(11, 18, 77.9, 78.85)) # limits in decimal degrees

basemap("arctic50", limits = c(3*10^6, -3*10^6, 3*10^6, -3*10^6)) # limits in uTM coordinates

Note that some map types are already limited, so if you are looking for a map of Kongsfjorden, using basemap("kongsfjorden") might be just what you need.

Automatic limits

Requires a character vector: the first element gives the object name of the data frame containing data to which the map should be limited, the second argument gives the column name of longitude data and the third argument the column name of latitude data. The map will be limited using rounded minimum and maximum floor and ceiling values for longitude and latitude. Use the limits.lon and limits.lat agruments to define the accuracy of rounding.

basemap(type = "svalbard", limits = c("kongsfjord_moorings", "Lon", "Lat"), limits.lon = 0.01, limits.lat = 0.01) + geom_point(data = kongsfjord_moorings, aes(x = lon.utm, y = lat.utm), color = "red")

Detailed bathymetry shapes

The default bathymetry shapefile is too low resolution to be used inside Svalbard fjords:

basemap("kongsfjorden", bathymetry = TRUE)

PlotSvalbard contains more detailed shapefiles from the Norwegian Mapping Authority, but these files have gaps in them. More detailed shapefiles can be plotted using the bathy.detailed argument (warning: detailed bathymetries are large and therefore slow.)

basemap("kongsfjorden", bathymetry = TRUE, bathy.detailed = TRUE)

Bathymetry styles

PlotSvalbard has 4 preprogrammed style alternatives:

basemap("barentssea", bathymetry = TRUE, bathy.style = "poly_blues") # default

basemap("barentssea", bathymetry = TRUE, bathy.style = "poly_greys") # grey polygons with shading

basemap("barentssea", bathymetry = TRUE, bathy.style = "contour_blues") # colored contours

basemap("barentssea", bathymetry = TRUE, bathy.style = "contour_grey") # grey contours

Adding depth labels to contours (ala nautical maps) is currently an unresolved issue.

Customizing bathymetry styles

The color scales for polygons and contours can be adjusted using ggplot2 syntax:

basemap("barentssea", bathymetry = TRUE) + scale_fill_viridis_d("Water depth (m)")
#> Scale for 'fill' is already present. Adding another scale for 'fill',
#> which will replace the existing scale.

basemap("barentssea", bathymetry = TRUE, bathy.style = "contour_blues") + scale_color_hue()
#> Scale for 'colour' is already present. Adding another scale for
#> 'colour', which will replace the existing scale.

Adding station labels (text)

Text can be added to basemaps using the geom_text() function:

data("npi_stations")

x <- transform_coord(npi_stations, lon = "Lon", lat = "Lat", bind = TRUE)

basemap("svalbard", limits = c(3,24,78.5,82), round.lat = 1, round.lon = 2, 
  land.col = "#a9750d", gla.border.col = "grey95") + 
  geom_text(data = x, aes(x = lon.utm, y = lat.utm, 
    label = Station), color = "red", fontface = 2)

Text size can be mapped to variables using the standard ggplot2 syntax:

data("kongsfjord_moorings")

basemap("kongsfjorden", limits = c(11.3, 12.69, 78.85, 79.1), round.lat = 0.05, round.lon = 0.5) + 
  geom_text(data = kongsfjord_moorings, aes(x = lon.utm, y = lat.utm, 
  label = Mooring.name, color = Name), fontface = 2, 
  size = 25.4/72.27*8) # font size = 8, see Graphical parameters

Adding piecharts

The scatterpie package allows relatively easy plotting of piecharts on maps. Extensions for ggplot2 work together with PlotSvalbard.

data(zooplankton)

x <- transform_coord(zooplankton, lon = "Longitude", lat = "Latitude", bind = TRUE)

species <- colnames(x)[!colnames(x) %in% c("lon.utm", "lat.utm", "ID",
  "Longitude", "Latitude", "Total")]

library(scatterpie)
#> 
#> Attaching package: 'scatterpie'
#> The following object is masked from 'package:sp':
#> 
#>     recenter

basemap("barentssea", limits = c(4, 24, 79.5, 83.5), round.lon = 2, round.lat = 1) + 
  geom_scatterpie(aes(x = lon.utm, y = lat.utm, group = ID, r = 100*Total), 
  data = x, cols = species, size = 0.1) + scale_fill_discrete(name = "Species", 
  breaks = species, labels = parse(text = paste0("italic(" , sub("*\\.", "~", species), ")")))

Adding interpolated 2D surfaces

PlotSvalbard uses the krige function from the gstat package to produce interpolated 2D plots:

data("chlorophyll")

x <- interpolate(chlorophyll, Subset = "From <= 10", value = "Chla") ## Interpolate
#> [inverse distance weighted interpolation]

plot(x, legend.label = "Chlorophyll-a\n(mg/m3)")